Flight policy determination at roaming

ABSTRACT

A system, method, node and computer program for determining a flight policy to be applied to an unmanned aerial vehicle, UAV, (10) is described. The UAV (10) is associated with a first UAV-Application Server, UAV-AS, (100) maintaining a flight policy applicable for a geographical service area (150) where the UAV (10) is located. The method comprising the first UAV-AS (100) determining whether the UAV (10) is going to leave the geographical service area (150) towards a second geographical service area (150). If so, determining by the first UAV-AS (100) a flight policy applicable for the second geographical service area (150), wherein that flight policy is maintained by a second UAV-AS (130). The method also comprises that the first UAV-AS (100) instructs the determined flight policy to the UAV (10), before the UAV (10) has entered the second geographical service area (150).

TECHNICAL FIELD

The present invention relates to flight safety and telecommunications,and in particular to a system, method, node and computer program fordetermination of a flight policy for a roaming Unmanned Aerial Vehicle,UAV.

BACKGROUND

An unmanned aerial vehicle, UAV, commonly known as a drone, is anaircraft without a human pilot aboard, whose flight may either beoperated under remote control by a human operator or autonomously byonboard computers. Nowadays, UAVs have been adopted for a wide varietyof applications. While, originally, UAVs have mainly been used formilitary applications, their use has rapidly been expanded to otherapplications over the recent years, including applications forsurveillance, peacekeeping, scientific research and commercial uses,such as in agriculture, product deliveries in logistics, aerialphotography, etc.

On flight, UAVs may be connected to application servers that are part ofground based control systems for flight safety via communicationsystems, such as cellular networks. Application servers may be run byUAV manufacturers, UAV operator, or other authorities for the purpose ofcontrolling and tracing the UAVs, for example. Each UAV manufacturer orauthority may run its own application server and UAVs can connect tothese servers via default Internet connections over-the-top (OTT, thusas transparent payload for the network operator) of the cellular networkby using an integrated cellular communication module. Although usage ofUAVs is regulated in most countries, UAV usage cannot be monitored andenforced by central agencies, such as central flight regulationauthorities or flight safety authorities, in order to restrict flightspaces or travel speeds and/or to manage flight paths, e.g., to providesecure travel paths for delivery services.

Here a dedicated UAV Application Server, UAV-AS, is assumed that shallbe used by any UAV using a cellular network when the UAV is turned-on.The UAV-AS is under the administrative domain of the network operatorand is automatically discovered. An UAV connects to a UAV-AS when theUAV is taken into service.

Flight regulation may differ in real-time depending on differentgeographical locations of the UAV or when certain borders are crossed.For example, the UAV is flying from one country to another (e.g.delivery service), or from unrestricted air space in a country to arestricted are (e.g. a city, stadium, military area, or other limitedair space).

Flight Policies such as flight restrictions (night flight not allowed,flight space restricted etc.) must be ensured at all times beforecrossing a border and entering that air space.

SUMMARY

Accordingly, there is a need for a technique which allows to determine acurrent flight policy applicable to a neighboring geographical areaalready before the UAV is entering that area.

This object is achieved by the independent claims. Advantageousembodiments are described in the dependent claims.

According to a first aspect of the invention, a method for determining aflight policy to be applied to an unmanned aerial vehicle, UAV, isprovided. The UAV is associated with a first UAV-Application Server,UAV-AS, maintaining a flight policy applicable for the geographicalservice area where the UAV is located. The method comprises determining,by the first UAV-AS, whether the UAV is going to leave the geographicalservice area towards a second geographical service area, anddetermining, by the first UAV-AS, a flight policy applicable for thesecond geographical service area, wherein the flight policy applicablefor the second geographical service area is maintained by a secondUAV-AS. The method also comprises instructing, by the first UAV-AS, thedetermined flight policy applicable for the second geographical serviceto the UAV, before the UAV has entered the second geographical servicearea.

According to another exemplary aspect of the invention, a method in anunmanned aerial vehicle application server, UAV-AS, for determining aflight policy to be applied to an unmanned aerial vehicle UAV, isprovided. The UAV is associated with the UAV-AS and the UAV-AS ismaintaining a flight policy applicable for the geographical service areawhere the UAV is located. The method comprises determining, by theUAV-AS, whether the UAV is going to leave the geographical service areatowards a second geographical service area, and determining, by theUAV-AS, a flight policy applicable for the second geographical servicearea, wherein the flight policy applicable for the second geographicalservice area is maintained by a second UAV-AS. The method furthercomprises instructing, by the UAV-AS, the determined flight policyapplicable for the second geographical service to the UAV, before theUAV has entered the second geographical service area.

According to a further exemplary aspect of the invention, a method in asuperior unmanned aerial vehicle application server, UAV-AS, fordetermining a flight policy to be applied to an unmanned aerial vehicleUAV, is provided. A plurality of UAV-AS are subordinate UAV-AS in ahierarchical structure of UAV-AS comprising at least one superior layerof UAV-AS comprising one or more superior UAV-AS, the subordinate UAV-ASand the superior layer of UAV-AS is arranged in the hierarchicalstructure such that each subordinate UAV-AS is tied to one superiorUAV-AS. The method comprises receiving, by the superior UAV-AS, arequest for a flight policy applicable for a geographical service area,and determining, by the superior UAV-AS, a flight policy applicable forthe geographical service area. The method further comprises returningthe determined flight policy.

According to an exemplary aspect of the invention, an unmanned aerialvehicle application server, UAV-AS, for determining a flight policy tobe applied to an unmanned aerial vehicle UAV, is provided. The UAV isassociated with the UAV-AS and the UAV-AS is maintaining a flight policyapplicable for the geographical service area where the UAV is located.The UAV-AS is adapted to determine whether the UAV is going to leave thegeographical service area towards a second geographical service area,and to determine a flight policy applicable for the second geographicalservice area, wherein the flight policy applicable for the secondgeographical service area is maintained by a second UAV-AS. The UAV-ASis further adapted to instruct the determined flight policy applicablefor the second geographical service to the UAV, before the UAV hasentered the second geographical service area.

According to another exemplary aspect of the invention, a superiorunmanned aerial vehicle application server, UAV-AS, for determining aflight policy to be applied to an unmanned aerial vehicle UAV, isprovided. A plurality of UAV-AS are subordinate UAV-AS in a hierarchicalstructure of UAV-AS comprising at least one superior layer of UAV-AScomprising one or more superior UAV-AS, the subordinate UAV-AS and thesuperior layer of UAV-AS is arranged in the hierarchical structure suchthat each subordinate UAV-AS is tied to one superior UAV-AS. Thesuperior UAV-AS is adapted to receive a request for a flight policyapplicable for a geographical service area, and determining a flightpolicy applicable for the geographical service area. The superior UAV-ASis further adapted to return the determined flight policy.

According to another exemplary aspect of the invention, a system fordetermining a flight policy to be applied to an unmanned aerial vehicle,UAV, is provided. The UAV is associated with a UAV-Application Server,UAV-AS, maintaining a flight policy applicable for the geographicalservice area where the UAV is located. The system comprises a pluralityof UAV-AS, one or more superior UAV-AS, and a plurality of UAV. Theplurality of UAV-AS are subordinate UAV-AS in a hierarchical structureof UAV-AS comprising at least one superior layer of UAV-AS comprisingthe one or more superior UAV-AS, the subordinate UAV-AS, and thesuperior layer of UAV-AS is arranged in the hierarchical structure suchthat each subordinate UAV-AS is tied to one superior UAV-AS.

Also provided is a computer program product comprising program codeportions to perform the steps of any of the methods presented hereinwhen executed on one or more processors. The computer program productmay be stored on computer readable recording medium such as asemiconductor/flash memory, DVD, and so on. The computer program productmay also be provided for download via a communication connection.

The foregoing and other objects, features and advantages of the presentinvention will become more apparent in the following detaileddescription of embodiments of the invention illustrated in theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the invention will becomebetter apparent from the detailed description of particular, but notexclusive embodiments, illustrated by way of non-limiting examples inthe accompanying drawings, wherein:

FIG. 1 a shows a diagram illustrating a hierarchical system of UAV-AScomprising a subordinate layer and two superior layers, superior layer 1and the superior layer 2 being the so called root;

FIG. 1 b shows a diagram illustrating a geographical mapping of areasinto service areas that are under administration of a UAV-AS, and agrouping of several service areas into a global service area;

FIG. 2 shows a signaling flow for querying a flight policy applicablefor a neighboring service area, specific for the case that the targetarea is tied to the same superior UAV-AS;

FIG. 3 shows a signaling flow for querying a flight policy applicablefor a neighboring service area, specific for the case that the targetarea is tied to a distant UAV-AS;

FIGS. 4 a and 4 b show a block diagrams illustrating a UAV-AS logic;

FIG. 5 shows a block diagrams illustrating a superior UAV-AS logic;

FIGS. 6 a and 6 b show an exemplary composition of a computing unitconfigured to execute a UAV-AS according to the present disclosure andan exemplary composition of a superior UAV-AS according to the presentdisclosure;

FIGS. 7 a and 7 b show an exemplary modular function composition of acomputing unit configured to execute a UAV-AS and an exemplary modularfunction composition of a computing unit configured to execute asuperior UAV-AS according to the present disclosure and a correspondingmethod which may be performed by UAV-AS and superior UAV-AS;

FIGS. 8 and 9 illustrate exemplary cellular network architectures forLTE and 5G including a UAV and UAV-AS, which may be used according tothe present disclosure.

DETAILED DESCRIPTION

In the following description, for purposes of explanation and notlimitation, specific details are set forth in order to provide athorough understanding of the present disclosure. It will be apparent toone skilled in the art that the present disclosure may be practiced inother implementations that depart from these specific details. Forexample, while the following implementations will be described withregard to LTE and 5G architectures, it will be understood that thepresent disclosure shall not be limited to these architectures and thatthe technique presented herein may be practiced with other cellularnetwork architectures as well.

Those skilled in the art will further appreciate that the steps,services and functions explained herein below may be implemented usingindividual hardware circuitry, using software functioning in conjunctionwith a programmed micro-processor or general purpose computer, using oneor more Application Specific Integrated Circuits (ASICs) and/or usingone or more Digital Signal Processors (DSPs). It will also beappreciated that when the present disclosure is described in terms of amethod, it may also be embodied in one or more processors and one ormore memories coupled to the one or more processors, wherein the one ormore memories are encoded with one or more programs that perform thesteps, services and functions disclosed herein when executed by the oneor more processors.

Within the context of the present application, the term “Unmanned AerialVehicle”, or UAV in short, refers to an automatic machine that can movein any given environment. UAV is considered synonym with “drone”, or“mobile robot”. Mobile robots have the capability to move around intheir environment, thus they are not fixed to one physical location. Incontrast, industrial robots usually consist of a jointed arm(multi-linked manipulator) and gripper assembly (or end effector) thatis attached to a fixed surface. A mobile robot may be classified by theenvironment in which it moves:

-   -   Land or home robots are usually referred to as Unmanned Ground        Vehicles. They are most commonly wheeled or tracked, but also        include legged robots with two or more legs (humanoid or        resembling animals or insects).    -   Aerial robots are usually referred to as Unmanned Aerial        Vehicles.    -   Underwater robots are usually called Autonomous Underwater        Vehicles or Unmanned Submarine Vessel.    -   Water surface based mobile robots are usually referred to as        Unmanned Marine Vehicles.

The above listed vehicles are the types of vehicles that moveautonomously, so without human pilot, on a programmed or instructed pathor towards an instructed geographical position/destination, or may alsobe steered and controlled remotely. The vehicle may also carry humanpassengers, but wherein none of these passengers would be involved insteering the vehicle. The vehicle may comprise a pilot or driver, butthe vehicle would operate in an autonomous movement mode where thedriver or pilot is released from the actual steering task. Autonomousdriving of a car or auto-pilot flight mode in aircrafts or ships wouldalso be examples covered by the term UAV.

These vehicles could operate respectively in the air, on land,underground, on sea and inland waters, in space or even on otherplanets/asteroids. The vehicles have an own engine respectively jet,propeller, wheel, crawler track, propeller screw, or hover propulsionand gear. The vehicles have the ability of exchanging data with eachother and/or to a controlling base wirelessly. A ground based cellularor wireless communication network may be employed to enable such dataexchange. Such a communication network may be run by a mobile operatorand thus a communication between a UAV and a controlling ground stationmay take place using the data communication services of thatcommunication network.

UAV may be deployed for transportation of goods, e.g. for delivery ofparcels from a reseller or shop to the end customer. They may also beused for postal services or mail delivery.

Within the context of the present application, the term “geographicalservice area” or “service area” refers to a region under a commonadministration/authority. In the context of UAV and flight policies,this refers to a geographical area where a certain flight policy, oraccess policy, is applicable. Such flight policy is typically issued byan authorized (e.g. governmental) office/agency being responsible for asave and controlled usage of mobile drones or UAVs in that region(flight safety authority).

Such a geographical service area would be characterized by theapplicable flight policy being deposited in an application server, AS,and thereby made accessible for anyone deploying UAVs in that region.The AS may be physically located in that area, or may be centralized(instantiated) somewhere in a remote/central data center (e.g. in a“cloud”), or may be implemented by a virtual network function. Even ifthe AS (or AS instance) may be distant to the geographical service area,still the geographical service area would be tied to one (logical) AS(instance), thus the AS can be queried for getting access to theapplicable flight policy.

Typically, such authorized (e.g. governmental) office/agency takesautonomous decisions on local flight policies in accordance with thelocal legislation. Flight policies may also comprise UAV categories(e.g. weight classes), dynamic policies (e.g. depending on time of theday or flight density in that area), or may consider access priorities(e.g. premium delivery service, or emergency/disaster recoveryservices).

A geographical service area may also be composed of one or moresub-areas of different nature. Although the geographical service area assuch is a legislative region (where a flight policy is applicable), suchsub-areas may be radio coverage areas used in the cellular/wirelesscommunication network such as tracking areas, radio cells, locationareas, routing areas, or segments of a grid defined by e.g. GPScoordinates.

Within the context of the present application, the term “cellularnetwork” may denote a wireless communication network, or particularlydenote a collection of nodes or entities, related transport links, andassociated management needed for running a (communication) service, forexample a wireless telephony service or a wireless packet transportservice. Depending on the service, different node types or entities maybe utilized to realize the service. A network operator owns the cellularnetwork and offers the implemented services to its subscribers. Typicalcomponents of a wireless communication network are radio access network(such as 2G, GSM, 3G, WCDMA, CDMA, LTE, 5G, WLAN, Wi-Fi), mobilebackhaul network, and core network (such as PS Core, EPC, 5G Core).

Within the context of the present application, the term “hierarchicalstructure” of network elements refers to an arrangement of these networkelements in which the items are represented as being “above”, “below”,or “at the same layer as” one another. Hierarchy may comprise severallayers. Certain terminology is tied to a hierarchical structure.Superior refers to a higher layer or an object ranked at a higher layer(parent or ancestor), so being “above”. Subordinate refers to a lowerlayer or an object ranked at a lower layer (child or descendent), sobeing “below”. Peer refers to an object with the same rank, thus “at thesame layer”.

In a multi-layered hierarchical structure, the terms superior andsubordinate are universally applicable. E.g. in a three layeredhierarchical structure, there would be a “bottom” layer, a “top” layer,and a “middle” layer between those. For an element on the bottom layer,an element on the middle layer would be superior. At the same time, foran element on the middle layer, an element on the top layer would alsobe superior. This applies also for the downward direction: For anelement on the top layer, an element on the middle layer would besubordinate. At the same time, for an element on the middle layer, anelement on the bottom layer would also be subordinate.

Thus, superior refers to an element on “layer+1”, and subordinate refersto an element “layer−1”. This also means that the top layer element hasno superior element, and there is just one single element on that layer.An element on the bottom layer has no subordinate element, and thislayer comprises typically the most elements.

A key characteristic of a hierarchical structure is that each element istied to only one (superior) element on the next higher layer, with theexception of the top layer, which is therefore also called “root”. Theother way around, an element on a layer other than the bottom layer,sees one or more (subordinate) elements that are tied to him.

Now referring to FIG. 1 a , this figure shows a diagram illustrating anexample of a hierarchical system of UAV-AS elements.

A hierarchical system may comprise two or more layers. This figuressketches an example having three layers, a bottom layer comprisingUAV-AS 1 to 4, a middle layer comprising two superior UAV-AS 1 and 2,and a top (or root) layer comprising a root UAV-AS. Each UAV-AS is tiedto one UAV-AS on the next superior layer (except the top layer). Forexample, UAV-AS 1 100 is tied to a superior UAV-AS 1 110. UAV-AS 4 100is tied to a superior UAV-AS 2 110. Both, superior UAV-AS 1 and 2 aretied to the top layer root UAV-AS 120.

As indicated in the figure, superior UAV-AS 2 may have connections tomore than 2 subordinate UAV-AS. Also the single root layer UAV-AS may beconnected to more than 2 UAV-AS on the middle layer.

A UAV 10 discovers and connects to a single UAV-AS 100 when the UAV isturned-on. A UAV 10 would not connect to a UAV-AS on the middle or toplayer.

Now referring to FIG. 1 b , this figure shows a diagram illustrating ageographical mapping of areas into service areas that are underadministration of a UAV-AS, and a grouping of several service areas intoa global service area.

A UAV-AS 100 is assumed to be responsible for a geographical area, herecalled UAV-AS service area 150 covering a certain geographical area. TheUAV-AS 100 maintains a flight policy applicable for all UAV 10 beingpresent in that geographical area the UAV-AS 100 is responsible for(i.e. the service area).

The geometrical shape of a UAV-AS service area 150 may depend ondifferent factors. A basic shape would be a circle or elliptical shape.However, it is assumed that an entire geographical area (e.g. a country)is subject to a one or more flight policies, and that if a UAV 10 isleaving a first service area, it immediately enters a second servicearea. The geometrical shape that best covers a larger region would be asquare/rectangle or a hexagonal shape. For this reason, this figuresketches a scenario where the service area would be hexagonal shaped.

A service area may also be composed of one or more radio coverage areasused in the cellular network such as tracking areas, radio cells,location areas, routing areas, or grids segments. In this case, theshape of the underlying radio coverage areas may implicitly determinethe shape of the service area, and is determined by radio wavepropagation in a real world condition.

A UAV 10 may be residing in a cellular network comprising a plurality ofradio coverage areas and the geographical service area 150 is composedof one or more radio coverage areas used in the cellular network.

If a superior UAV-AS 110 has more than one subordinate UAV-AS 100, thegeographical service area of the superior UAV-AS 110 is the geographicalservice area 160 of a merger of the geographical service areas 150 ofall subordinate UAV-AS 100 tied to the superior UAV-AS 110. In thisfigure, assuming that UAV-AS 1-7 are all tied to a single superiorUAV-AS 110, that superior UAV-AS 110 would be responsible for thegeographical service area 160 (here simplified as circle shaped).

Now referring to FIG. 2 , this figure shows a signaling flow forquerying a flight policy applicable for a neighboring service area,specific for the case that the target area is tied to the same superiorUAV-AS.

In step 210 the UAV-AS 100 is determining that a UAV 10 is about toleave the geographical service area 150 towards a second geographicalservice area 150. Thus the UAV-AS 100 must instruct the UAV 10 on aflight policy applicable for the targeted second geographical servicearea 150. The UAV 10 shall be instructed before the UAV 10 has enteredthe targeted second geographical service area 150. The flight policyapplicable for that targeted second geographical service area 150 mayimply flight restriction, so the UAV 10 must be instructed alreadybefore entering that targeted second geographical service area 150, toenable the UAV 10 to obey such restrictions and for example change theflight path or land in the current geographical service area 150.

When moving from one geographical service area 150 to a furthergeographical service area 150, the UAV 10 may have to change itsconnectivity. The geographical service area a UAV-AS is responsible for,may be constructed from one or more radio areas of a wireless network.The UAV may comprise a radio module (and a type of subscriber identitymodule, SIM, card) which may be used to register the UAV 10 into thewireless network. After successful registration, the UAV 10 may then usethe connectivity provided by the wireless network for its communicationwith the UAV-AS. When moving into a new geographical service area, theUAV 10 may have to disconnect from the former wireless network first,and then register into a wireless network available at the newgeographical service area. This change may cause a small interruption inconnectivity when entering the new geographical service area, and thusthe UAV 10 must be instructed on the applicable flight policy in thatgeographical service area, before moving into that new geographicalservice area.

The flight policy for the targeted second geographical service area 150is maintained by a second UAV-AS 130. Since the UAV-AS 100 has noknowledge on which UAV-AS would be responsible for that targeted secondgeographical service area 150 and consequently has also no knowledge onhow to address such second UAV-AS 130. The second UAV-AS 130 may forexample belong to a different country or a different administrative orlegal domain, such that a direct communication would not be appropriate,not allowed, or not possible.

The UAV-AS 100 may determine the second geographical service area 150based on flight path information applicable for the UAV 10. The UAV-AS100 may receive such flight path information applicable for the UAV 10from the UAV 10. In this case the UAV 10 may provide such information tothe UAV-AS, for example when entering a new service area. Byalternative, the UAV-AS 100 may receive the flight path informationapplicable for the UAV 10 from an operator operating the UAV 10. In thiscase the operator operating the UAV 10 may inform beforehand theresponsible UAV-AS along a scheduled flight path.

In this example flow, the UAV-AS are organized in a hierarchicalstructure, wherein a first UAV-AS 100 and a second UAV-AS 130 aresubordinate UAV-AS in a hierarchical structure of UAV-AS comprising atleast one superior layer of UAV-AS comprising one or more superiorUAV-AS 110, the subordinate UAV-AS 100 and the superior layer of UAV-ASbeing arranged in the hierarchical structure such that each subordinateUAV-AS 100 is tied to one superior UAV-AS 110. Thus the UAV-AS 100 is asubordinate UAV-AS and is tied to a superior UAV-AS 110 on the nextlayer of the hierarchy.

To build up this tie to a superior UAV-AS 110, a subordinate UAV-AS 100may registers itself towards that superior UAV-AS 110 and indicating ageographical service area 150 the subordinate UAV-AS 100 is responsiblefor. Such registration may take place at an initial start of the UAV-AS100. An established registration, and thereby and established tie to asuperior UAV-AS 110, may be reconfirmed/renewed at periodic intervals.

In order to determine the flight policy applicable for the targetedsecond geographical service area 150, the UAV-AS 100 sends a policyquery request message 220 to its superior UAV-AS 110, so the superiorUAV-AS 110 the UAV-AS 100 is tied to. This message comprises anindication of the targeted second geographical service area 150.

The superior UAV-AS 110 receives the request 220 for a flight policy foran indicated geographical service area 150. In step 230 the superiorUAV-AS 110 determines, based on the received indicated geographicalservice area 150, whether the indicated geographical service area 150 iswithin the geographical service area the superior UAV-AS 110 isresponsible for. As explained above, the geographical service area ofthe superior UAV-AS 110 is the geographical service area 160 of a mergerof the geographical service areas 150 of all subordinate UAV-AS 100 tiedto the superior UAV-AS 110.

In this example flow it is assumed that the superior UAV-AS 110 isresponsible for the indicated geographical service area 150. Thus instep 240, the check results into a ‘yes’. The superior UAV-AS 110 thendetermines the responsible UAV-AS 130 maintaining the flight policy forthe indicated geographical service area 150. In step 240 the superiorUAV-AS 110 then sends a policy query message 250 to the identifiedresponsible UAV-AS 130, the responsible UAV-AS 130 being a subordinateUAV-AS located on a layer below the superior UAV-AS 110. The message maycomprise an indication of the geographical service area 150. That policyquery message 250 may be constructed by forwarding the received message220.

The target UAV-AS 130 receives in step 250 a query message requesting aflight policy for an indicated geographical service area 150. The targetUAV-AS 130 then in step 260 determines the applicable flight policy forthe indicated geographical service area 150. In step 270 the targetUAV-AS 130 returns the determined flight policy to the requestingsuperior UAV-AS 110.

The superior UAV-AS 110 receives in step 270 the determined flightpolicy from the target UAV-AS 130. The superior UAV-AS 110 then returnsin step 280 the received flight policy to the requesting UAV-AS 100. Thereturn message may be constructed by forwarding the received message270.

The UAV-AS 100 receives in step 280 the flight policy from the targetUAV-AS 130. In step 290 the UAV-AS 100 instructs the UAV 10 according tothe received flight policy.

A flight policy may comprise restrictions in respect of operation and/ormovement of the UAV 10. A restriction in UAV movement may comprise oneor more of: applicable speed limits, yield rules, flight heightrestrictions, flight path restrictions, flight noise restrictions. Thesemay either on a permanent level, or for given restriction times. Flightpolicies may also be applicable for certain UAV categories (e.g. weightclasses, sizes, noise classes, payload classes), be of dynamic nature ortemporary, e.g. depending on time of the day, UAV flight density in thatarea, or may consider access/flight priorities, e.g. premium deliveryservice, or emergency/disaster recovery services.

Instructing a UAV 10 may comprise that the responsible UAV-AS 100 sendsthe applicable flight restriction to the UAV 10, so leaving it up to theUAV 10 to take appropriate actions to comply with the flight policy.Thus the UAV-AS 100 may instruct the UAV 10 by providing flightinstructions corresponding to the flight policy to the UAV 10.

By alternative, the UAV-AS 100 may interpret the flight policy andderive appropriate actions/instructions corresponding to the flightpolicy. The UAV-AS 100 informs the UAV 10 about the actions to be takenby the UAV 10. In this case the UAV-AS 100 decides on the appropriateactions to comply with the flight policy, and the UAV 10 is expected tofollow these actions after being instructed/informed.

Typical actions could be an instruction to land and not enter thetargeted second geographical service area 150. Instead of landing, theUAV 10 could be instructed to change the flight path and take a detourvia a further geographical service area to reach the destination. In yetanother alternative, the UAV 10 could be instructed to enter thetargeted second geographical service area 150 at an alternative entrypoint. As a last resort, the UAV 10 may be instructed to return to thestarting base, for example if no meaningful instruction could be derivedas all possible target service areas are restricted, except the one theUAV came from (dead end situation).

Now referring to FIG. 3 , this figure shows a signaling flow forquerying a flight policy applicable for a neighboring service area,specific for the case that the target area is tied to a distant UAV-AS.

This flow takes up the same use case as shown in FIG. 2 , showing thatthe question in step 230 is answered with ‘no’.

So steps 210, 220, 230 are the same as described for FIG. 2 . But inthis embodiment, the superior UAV-AS 110 is not responsible for theindicated geographical service area 150, and thus no responsiblesubordinate UAV-AS 100 could be determined by the superior UAV-AS 110,but the superior UAV-AS (110) is tied to a further superior UAV-AS 110on a next higher hierarchy layer.

Thus in step 300, the check results into a ‘no. The superior UAV-AS 110then escalates the flight policy query request to a next higher layerUAV-AS, by sending message 310 comprising the indicated geographicalservice area 150. This message 310 may be constructed by forwarding thereceived message 220.

In this example it is assumed (in alignment with FIG. 1 a ) that thehierarchical structure of UAV-AS comprises three layer. Thus, if thesuperior UAV-AS 110 escalates the query, that escalation is targetingthe highest layer of the hierarchical structure. On this highest layeronly a single UAV-AS, the so called root UAV-AS 120 is located. Thatroot UAV-AS 120 has global responsibility and can always identify asubordinate responsible UAV-AS on the next lower layer.

Thus in step 320 the root UAV-AS 120 determines the responsiblesubordinate UAV-AS 110. In step 330 the root UAV-AS 120 send a flightpolicy query request message to the identified subordinate UAV-AS 110.That message comprising the indicated geographical service area 150.

The handling in the subordinate UAV-AS 110 is the same as shown in steps230 to 270 above. The UAV-AS 110 identifies the responsible subordinateUAV-AS 100, which determines the flight policy, and returns it to thevia the UAV-AS 110 to the root UAV-AS 120 in message 340.

The root UAV-AS 120 then returns the received flight policy in message350 to the superior UAV-AS 110, which then returns it to the requestingUAV-AS 100 in message 280 as shown already in the FIG. 2 above.

The receiving UAV-AS 100 will then instruct the UAV as shown in step 290above.

The basic principle of fetching a flight policy of a neighboringgeographical service area 150 is to always go ‘upwards’ to the nexthigher layer in the hierarchy of UAV-AS, until a responsible UAV-AS isfound. Then go ‘downwards’ in the hierarchy of UAV-AS to the subordinateUAV-AS maintaining the applicable flight policy for the geographicalservice area in question. The determined flight policy is then returnedto the requesting UAV-AS by backtracking the same path across thehierarchy.

Now referring to FIG. 4 a , this figure shows a block diagramsillustrating a UAV-AS logic. This block flow may be a used in asubordinate UAV-AS 100 as illustrated in the previous figures.

The flow starts in step 410 when the UAV-AS receives an indication ofthe target destination of a UAV, or other information indicative for aflight path the UAV is going to take. Based on this information, theUAV-AS determines in 420 that the UAV is going to leave the currentservice area towards a further service area. Typically, the furtherservice area is adjacent or neighboring to the current service area.Thus based on the flight information from the UAV, the UAV-AS determinesthe target service area the UAV is going to enter soon.

In step 430 the UAV-AS determines the flight policy applicable for thattarget service area. To do this, the UAV-AS sends a flight policy queryrequest message to the superior UAV-AS the UAV-AS is tied to. Suchconnection to a superior UAV-AS may be established at start-up of theUAV-AS, for example during a registration phase, by look-up, or byadministration in the UAV-AS. The query to the superior UAV-AS comprisesan indication of the target service area.

In step 440 the UAV-AS receives a response from the queried superiorUAV-AS. The response comprises the flight policy applicable for thetarget service area.

In step 450 the UAV-AS instructs the UAV according to the flight policy,as already described above.

Now referring to FIG. 4 b , this figure shows a block diagramsillustrating a UAV-AS logic. This block flow may be a used in asubordinate UAV-AS 100 as illustrated in the previous figures.

In step 460 the UAV-AS receives a request to provide a flight policy.This request may comprise an indication of the targeted service area.The UAV-AS verifies that the request is for the service area the UAV-ASholds the flight policy for.

In step 470 the UAV-AS then determines the local flight policy andreturns it in step 480 to the requesting UAV-AS.

This block flow may correspond to steps 250 to 270 in FIG. 2 , thus sucha request may typically come from a superior UAV-AS.

Now referring to FIG. 5 , this figure shows a block diagramsillustrating a superior UAV-AS logic. This block flow may be a used in asuperior UAV-AS 110 or root UAV-AS 120 as illustrated in the previousfigures.

The flow starts in step 510 when the superior UAV-AS receives a flightpolicy query request message comprising an indication of a targetedgeographical service area.

Such request may correspond to message 220 in FIGS. 2 and 3 and mayoriginate from a subordinate UAV-AS.

In step 520 the superior UAV-AS determines whether the superior UAV-ASis responsible for the service area indicated in the request. Is so, sothe superior UAV-AS is responsible for the service area indicated in therequest, the flow continues with step 550. If not, so the superiorUAV-AS is not responsible for the service area indicated in the request,the flow continues with step 530.

In step 530 the superior UAV-AS determined that it is not responsiblefor the geographical service area indicated in the request. Thus therequest must be escalated to the next higher layer in the hierarchy ofUAV-AS. The superior UAV-AS sends a flight policy query request message,comprising an indication of a targeted geographical service area, to thenext higher layer superior UAV-AS.

In step 540 the superior UAV-AS receives a response to the request fromthe superior UAV-AS comprising the determined flight policy.

In step 550 the superior UAV-AS determined that it is responsible forthe geographical service area indicated in the request. Thus the requestmust be forwarded downwards in the hierarchy to the next lower layer.The superior UAV-AS sends a flight policy query request message,comprising an indication of a targeted service area, to the next lowerlayer subordinate UAV-AS.

In step 560 the superior UAV-AS receives a response to the request fromthe subordinate UAV-AS comprising the determined flight policy.

In step 570 the superior UAV-AS returns the determined flight policy tothe requesting subordinate UAV-AS.

Now referring to FIG. 6 a , this figure shows an exemplary compositionof a computing unit 600 configured to execute a UAV-AS according to thepresent disclosure. The UAV-AS may be the UAV-AS 100 as shown in theprevious figures.

The computing unit 600 comprises at least one processor 610 and at leastone memory 620, wherein the at least one memory 620 containsinstructions executable by the at least one processor 610 such that thecomputing unit 600 is operable to carry out the method steps describedin FIGS. 4 a and 4 b with reference to the UAV-AS 100.

Now referring to FIG. 6 b , this figure shows an exemplary compositionof a computing unit configured to execute a superior UAV-AS according tothe present disclosure. The superior UAV-AS may be the superior UAV-AS110 as shown in the previous figures.

The computing unit 650 comprises at least one processor 660 and at leastone memory 670, wherein the at least one memory 670 containsinstructions executable by the at least one processor 660 such that thecomputing unit 650 is operable to carry out the method steps describedin FIG. 5 with reference to the superior UAV-AS 110.

It will be understood that the computing units 600 and 650 may bephysical computing units as well as virtualized computing units, such asvirtual machines, for example. It will further be appreciated that thecomputing units may not necessarily be implemented as standalonecomputing units, but may be implemented as components—realized insoftware and/or hardware—residing on multiple distributed computingunits as well.

Now referring to FIG. 7 a , this figure shows an exemplary modularfunction composition of a computing unit configured to execute a UAV-ASaccording to the present disclosure and a corresponding method which maybe performed by a UAV-AS, in particular the UAV-AS 100 as presentedbefore.

The Transceiver Module 710 may be adapted to perform reception andsending of signaling messages, such as step 410, 440, 460, 480, and anysignaling messages related to the determination of a flight policy for aUAV about to leave a current geographical service area towards a furthergeographical service area.

The Flight Policy Handling Module 720 may be adapted to maintain aflight policy for the own geographical service area. On request, theFlight Policy Handling Module 720 provides the own flight policy asshown in step 470. The reception of a corresponding request and thesending of a response with the flight policy may be done together withthe Transceiver Module 710.

The UAV Flight Path Supervision Module 730 may be adapted to supervisethe flight of UAV within the own geographical service area. The UAVFlight Path Supervision Module 730 may determine that a UAV is going toleave the own geographical service area and also determine the targetedneighbouring geographical service area as of step 420. The UAV FlightPath Supervision Module 730 may receive information of the flight pathof a UAV from the UAV itself or from an operator of the UAV. The UAVFlight Path Supervision Module 730 may instruct the UAV on a flightpolicy or appropriate actions corresponding to a flight policy as ofstep 450.

The Policy Query Module 740 may be adapted to handle a query for aflight policy from a superior UAV-AS as of step 430 and 440. The sendingof a request and reception of a corresponding response comprising theflight policy may be done together with the Transceiver Module 710.

Now referring to FIG. 7 b , this figure shows an exemplary modularfunction composition of a computing unit configured to execute asuperior UAV-AS according to the present disclosure and a correspondingmethod which may be performed by a superior UAV-AS, in particular thesuperior UAV-AS 110 as presented before.

The Transceiver Module 760 may be adapted to perform reception andsending of signaling messages, such as step 510, 530, 540, 550, 560,570, and any signaling messages related to the determination of a flightpolicy for a UAV about to leave a current geographical service areatowards a further geographical service area.

The Service Area Determination Module 770 may be adapted to determinewhether an indicated geographical service area resides within the owngeographical service area as of step 520.

The Policy Query Module 740 may be adapted to handle a query for aflight policy from a superior UAV-AS as of step 530 and 540, or tohandle a query a flight policy from a subordinate UAV-AS as of step 550and 560. The sending of a request and reception of a correspondingresponse comprising the flight policy may be done together with theTransceiver Module 710.

Now referring to FIG. 8 , this figure illustrates exemplary cellularnetwork architecture for LTE including a UAV and UAV-AS, which may beused according to the present disclosure.

A radio coverage area of an LTE network is based on tracking areas. Insuch example, the geographical service area a UAV-AS is responsible for,may be constructed from one or more tracking areas of the LTE radionetwork. The UAV may comprise a LTE-radio module (and a type ofsubscriber identity module, SIM, card) which is used to register the UAVinto the packet core network of the network operator. Once beingregistered, or as part of the registration procedure, the UAV maydiscover the UAV-AS being responsible for the current geographicalservice are. The normal mobility procedures of the packet core networkare used to keep track on the mobility of the UAV. This architecture issketched in FIG. 8 in more detail.

As common LTE architectures, the architecture shown in FIG. 8 comprisesan eNodeB 820 through which the UAV 810 may connect to the cellularnetwork using an e-Uu interface. The eNodeB 820 connects to a MobilityManagement Entity, MME, 800 for control plane support using an S1-MMEinterface and to a Packet Data Network Gateway, PDN GW, 830 for userplane support (i.e., for user data transfer) using an S1-U interface.The MME 800, in turn, is connected to a Home Subscriber Service, HSS,840 containing user-related and subscription-related information via anS6a interface. It will be understood by the skilled person that thearchitecture shown in FIG. 8 corresponds to a simplified LTEarchitecture in which only those components that are necessary for thepurpose of elucidating the technique presented herein are shown.

In addition to the above-described common entities of an LTE network,the architecture illustrated in FIG. 8 further comprises a UAVapplication server 850 (denoted as “UAV-AS” in the figure) as part ofthe cellular communication network. The UAV-AS 850 may correspond to theUAV-AS described in relation to the previous figures. The UAV-AS 850connects to the PDN GW 830 through an SGi interface and supports anexternal interface which allows access to functions of the UAV-AS 850 toentities external to the cellular communication network, such asentities accessing the UAV-AS 850 from the Internet, or vice versa, forexample.

Using the SGi interface to the packet core network, the UAV-AS cancommunicate with the UAV and vice versa. This allows to instruct aflight policy or corresponding actions to a UAV and to receive flightpath information from the UAV in the UAV-AS. Via the interface toexternal networks such as the Internet, the UAV-AS is able to retrieveand provide information from an operator of the UAV, or to contact otherUAV-AS of a hierarchical UAV-AS architecture.

Now referring to FIG. 9 , this figure illustrates exemplary cellularnetwork architectures for 5G including a UAV and UAV-AS, which may beused according to the present disclosure.

The architecture shown in FIG. 9 corresponds to a 5G variant of thearchitecture described in relation to FIG. 8 . The basic principles forpracticing the technique presented herein may equally apply to the 5Garchitecture of FIG. 9 . Unnecessary repetitions are thus omitted in thefollowing. Only, it is noted that the functions described above for theeNodeB, the MME, the PDN GW and the HSS may in this case be performed bycorresponding functions of the 5G architecture, i.e., the Radio AccessNetwork, RAN, 120, the Access and Mobility Function, AMF, 100, the UserPlane Function, UPF, 130, and the User Data Management, UDM, 140,respectively.

According to another embodiment, a computer program is provided. Thecomputer program may be executed by the computing units 600 and/or 650of the above mentioned entities UAV-AS and superior UAV-AS respectivelysuch that a method for handling flight policies determination at roamingas described above with reference to FIG. 4 a, 4 b or 5 may be carriedout or be controlled. In particular, the entities UAV-AS and superiorUAV-AS may be caused to operate in accordance with the above describedmethod by executing the computer program.

The computer program may be embodied as computer code, for example of acomputer program product. The computer program product may be stored ona computer readable medium, for example a disk or the storing unit 620and/or 670 of the UAV-AS and superior UAV-AS, or may be configured asdownloadable information.

One or more embodiments as described above may enable at least one ofthe following technical effects:

-   -   Supervision of the flight of a UAV and determination, that a UAV        is about to leave the current service area where a particular        flight policy is applicable.    -   Determination of a flight policy applicable for the service area        the UAV is about to enter, and instructing the flight policy to        the UAV before the UAV is leaving the current service are.    -   Minimizing the administrative relation between authority domains        maintaining an own flight policy, by hierarchical escalation of        flight policy queries. A UAV-AS has just a single interface for        determining a flight policy.

Modifications and other embodiments of the disclosed invention will cometo mind to one skilled in the art having the benefit of the teachingspresented in the foregoing descriptions and the associated drawings.Therefore, it is to be understood that the embodiments are not to belimited to the specific embodiments disclosed and that modifications andother embodiments are intended to be included within the scope of thisdisclosure. Although specific terms may be employed herein, they areused in a generic and descriptive sense only and not for purposes oflimitation.

It is believed that the advantages of the technique presented hereinwill be fully understood from the foregoing description, and it will beapparent that various changes may be made in the form, constructions andarrangement of the exemplary aspects thereof without departing from thescope of the invention or without sacrificing all of its advantageouseffects. Because the technique presented herein can be varied in manyways, it will be recognized that the invention should be limited only bythe scope of the claims that follow.

The invention claimed is:
 1. A method implemented by a first subordinateunmanned aerial vehicle application server (UAV-AS) in a hierarchicalUAV-AS structure for determining a flight policy to be applied to anunmanned aerial vehicle (UAV) located in a first geographical servicearea of the first subordinate UAV-Application Server (UAV-AS), themethod comprising: determining whether the UAV is going to leave thefirst geographical service area towards a second geographical servicearea; sending, by the first subordinate UAV-AS, a request for a flightpolicy applicable for the second geographical service area to a superiorUAV-AS in the hierarchical UAV-AS structure, wherein the flight policyapplicable for the second geographical service area is maintained by asecond subordinate UAV-AS in the hierarchical UAV-AS structure;receiving from the superior UAV-AS the flight policy for the secondgeographical service area; and instructing the determined flight policyapplicable for the second geographical service to the UAV, before theUAV has entered the second geographical service area.
 2. The method ofclaim 1, wherein a flight policy comprises restrictions on operationand/or movement of the UAV.
 3. The method of claim 1, wherein the UAV isresiding in a cellular network comprising a plurality of radio coverageareas and the second geographical service area is composed of one ormore radio coverage areas used in the cellular network.
 4. The method ofclaim 1, wherein the first subordinate UAV-AS instructs the UAV byproviding flight instructions corresponding to the flight policy to theUAV.
 5. The method of claim 1, wherein the first subordinate UAV-ASdetermines the second geographical service area based on flight pathinformation applicable for the UAV.
 6. The method of claim 5, whereinthe first subordinate UAV-AS receives the flight path informationapplicable for the UAV from the UAV.
 7. The method of claim 5, whereinthe first subordinate UAV-AS receives the flight path informationapplicable for the UAV from an operator operating the UAV.
 8. The methodof claim 1: wherein the first subordinate UAV-AS and the secondsubordinate UAV-AS are subordinate UAV-AS in the hierarchical structureof UAV-AS comprising at least one superior layer of UAV-AS comprisingone or more superior UAV-AS; wherein the subordinate UAV-AS and thesuperior layer of UAV-AS are arranged in the hierarchical structure suchthat each subordinate UAV-AS is tied to one superior UAV-AS.
 9. Themethod of claim 8, wherein the superior UAV-AS is responsible for ageographical service area equivalent to a merger of the geographicalservice areas of all subordinate UAV-AS tied to the superior UAV-AS. 10.The method of claim 8, further comprising the superior UAV-AS receivinga request for providing a flight policy for the geographical servicearea the superior UAV-AS is responsible for.
 11. The method of claim 10,further comprising the superior UAV-AS: determining the flight policyfor the geographical service area; and returning, as a response to thereceived request, the flight policy for the geographical service areathe superior UAV-AS is responsible for.
 12. A method implemented by asuperior unmanned aerial vehicle application server (UAV-AS) fordetermining a flight policy to be applied to an unmanned aerial vehicle(UAV), wherein a plurality of UAV-AS are subordinate UAV-AS in ahierarchical structure of UAV-AS comprising at least one superior layerof UAV-AS comprising one or more superior UAV-AS, wherein the superiorunmanned aerial vehicle application server is located in the at leastone superior layer, the subordinate UAV-AS and the superior layer ofUAV-AS being arranged in the hierarchical structure such that eachsubordinate UAV-AS is tied to one superior UAV-AS, wherein the superiorUAV-AS is responsible for a geographical service area of a merger of thegeographical service areas of all subordinate UAV-AS tied to thesuperior UAV-AS, the method comprising: receiving a request for a flightpolicy applicable for a geographical service area from the subordinateUAV-AS, to which the superior UAV-AS is tied to; determining a flightpolicy applicable for the geographical service area; and returning thedetermined flight policy to the subordinate UAV-AS to which the superiorUAV-AS is tied to.
 13. The method of claim 12, wherein the superiorUAV-AS is responsible for a geographical service area of a merger of thegeographical service areas of all subordinate UAV-AS tied to thesuperior UAV-AS.
 14. The method of claim 12, wherein the determining aflight policy applicable for the geographical service area comprises,the superior UAV-AS determining, if the geographical service area iswithin the geographical service area the superior UAV-AS is responsiblefor, a subordinate UAV-AS responsible for the geographical service area.15. The method of claim 12, wherein the determining a flight policyapplicable for the geographical service area comprises the superiorUAV-AS forwarding, if the geographical service area is outside thegeographical service area the superior UAV-AS is responsible for, therequest to a next higher hierarchy layer superior UAV-AS.
 16. A firstsubordinate unmanned aerial vehicle application server (UAV-AS) fordetermining a flight policy to be applied to an unmanned aerial vehicle(UAV) located in a first geographical service area of the firstsubordinate UAV-AS, the UAV-AS comprising: processing circuitry; memorycontaining instructions executable by the processing circuitry wherebythe first subordinate UAV-AS is operative to: determine whether the UAVis going to leave the first geographical service area towards a secondgeographical service area; send, by the first subordinate UAV-AS, arequest for a flight policy applicable for the second geographicalservice area, wherein the flight policy applicable for the secondgeographical service area is maintained by a second subordinate UAV-ASin the hierarchical UAV-AS structure; receive from the superior UAV-ASthe flight policy for the second geographical service area; and instructthe determined flight policy applicable for the second geographicalservice to the UAV, before the UAV has entered the second geographicalservice area.
 17. A superior unmanned aerial vehicle application server(UAV-AS) for determining a flight policy to be applied to an unmannedaerial vehicle (UAV), wherein a plurality of UAV-AS are subordinateUAV-AS in a hierarchical structure of UAV-AS comprising at least onesuperior layer of UAV-AS comprising one or more superior UAV-AS, whereinthe superior unmanned aerial vehicle application server is located inthe at least one superior layer, the subordinate UAV-AS and the superiorlayer of UAV-AS arranged in the hierarchical structure such that eachsubordinate UAV-AS is tied to one superior UAV-AS, wherein the superiorUAV-AS is responsible for a geographical service area of a merger of thegeographical service areas of all subordinate UAV-AS tied to thesuperior UAV-AS, the superior UAV-AS comprising: processing circuitry;memory containing instructions executable by the processing circuitrywhereby the superior UAV-AS is operative to: receive a request for aflight policy applicable for a geographical service area from thesubordinate UAV-AS, to which the superior UAV-AS is tied to; determine aflight policy applicable for the geographical service area; and returnthe determined flight policy to the subordinate UAV-AS to which thesuperior UAV-AS is tied to.